3,666 research outputs found
Thermal analysis, optimization and design of a Martian oxygen production plant
The objective is to optimally design the thermal components of a system that uses carbon dioxide (CO2) from the Martian atmosphere to produce oxygen (O2) for spacecraft propulsion and/or life-support. Carbon dioxide is thermally decomposed into carbon monoxide (CO) and O2 followed by the electrochemical separation of O2. The design of the overall system and its various individual components depends on, among other things, the fraction of the stoichiometric yield of O2 that can be realized in the system and the temperature of operation of the electrochemical separation membrane. The analysis indicates that a substantial reduction could be obtained in the mass and power requirements of the system if the unreacted CO2 were to be recycled. The concepts of an optimum temperature of the zirconia cell and impracticality of plant operation at low cell efficiencies are also discussed. The design of the thermal equipment is such that the mass and power requirements of the individual components and of the overall system are optimized
A New Shock Model for the Effect of Leptin on Body Weight Gain
The present study was designed to examine the dosage effect of the chronic Leptin infusion on body weight gain. Using a new shock model approach, the mean and variance for body weight gain were found. The results are consistent and the shock model concludes that if the dosage of the Leptin increases, the body weight gain decreases. Keywords: New Shock model, Leptin, neuroendocrine, neuropeptides. 2010 Mathematics Subject Classification: 97Mxx, 93A30, 74J4
Approaches of Analysis of Ogee Shaped Barrage Raft Floor on Varying Foundation Media
The analysis of ogee shaped barrage raft floor is a challenging task for the designers because of varying heterogeneous strata disposition, worst combination of loading conditions and functional requirements. A typical Indian barrage bay 3 and 4 has been chosen for analytical comparison between conventional and numerical approach. The behavior of ogee shaped barrage raft floor under representative load cases highlighted that conventional analytical approach i.e. Hetenyi’s method may prove to be inadequate for varying foundation media, which has been recommended by Indian standard code. Unlike the analytical approach, the numerical approach of analysis especially the finite element method with the help of digital computers is capable of accounting for the variation in foundation media, which is a pointer to the advantage of numerical modeling approach of analysis of a typical barrage structure especially the ogee shaped barrage raft floor. The conventional and numerical approaches have been compared to show the limitations of conventional approach and their implication on design estimates
An economic analysis of groundwater markets and water use efficiency in hard rock area of Hosur union Krishnagiri district of Tamil Nadu
Groundwater selling is a guarantee against deficiency rains in areas where farmers do not have access to surface water irrigation. Therefore, examination of groundwater market development and the efficiency of groundwater use under different water regimes needs to be studied. The objective of the study was (a) to analyse the structure and contact of groundwater markets and (b) to estimate the cost of ground water extraction and selling price in Hosur and Kaveripatinam taluks of Krishnagiri district, Tamil Nadu. Based on the Primary survey, water structures were analysed using simple statistics and measured efficiency by Data Envelopment Analysis. The groundwater market structure demonstrated that the number of irrigation water buyers grows as the size of the farm decreases, while the number of irrigation water sellers grows as the size of the farm increases. The efficiency of groundwater use is estimated by data envelop analysis. According to the data, in a sample of groundwater markets, the seller-buyer concentration ratio was 1:1.13. The cropping intensity and irrigation intensity were highest (89.13 and 93.19 %, respectively) for the self-user+seller category. The selling price of groundwater (Rs. 50 per tank) was marginally higher than the total cost of water extraction (Rs. 28.27 per tank), thereby implying the exploitative nature of groundwater markets. According to findings on input consumption and landholdings, water buyers are resource-strapped farmers who are unlikely to be able to afford the large investments required to install a well
Erratum: "Ferroelectric Materials for Microwave Tunable Applications” [J. Electroceram. 11, 5 (2003)]
Pseudo cholinesterase-diagnostic and prognostic value in organophosphorus poisoning
Background: Organophosphorus compound poisoning is a common clinical situation encountered in emergency department. The estimation of pseudo cholinesterase levels in plasma help to identify OP poisoning. Aim of this study was the levels of pseudo cholinesterase in plasma as a diagnostic aid in patients with suspected organophosphorus poisoning and to predict the prognosis and mortality based on pseudo cholinesterase activity.Methods: 390 cases of suspected organophosphorus compound poisoning were selected above 18 years of age. Detailed history and clinical examination were done. The serum levels of enzyme pseudo cholinesterase were estimated on 1st and 3rd and 6th day.Results: 61% were males, 39% were females. Age range 18-55 years. Most of the patients were admitted within 4 hours of consumption. 50% cases were mild, 26% were moderate and 24% were severe cases, Commonest clinical features were vomiting, diarrhea and abdominal cramps. Common signs were miosis (46%), difficulty in breathing (42%), cold calmmy skin, bradycardia. Patients who survived had raising values of enzyme levels and in patients who expired did not show much increase in enzyme values.Conclusions: In initial stages of poisoning, determining pseudo cholinesterase activity forms a reliable test. In patients who survived had values above 4300 U/L and showed increasing levels on successive days indicating better prognosis. Low values of enzymes in initial stages of poisoning as well as decreasing values on the third day indicate increased mortality
The minimum mean monopoly energy of a graph
The motivation for the study of the graph energy comes from chemistry, where the research on the so-called total pi - electron energy can be traced back until the 1930s. This graph invariant is very closely connected to a chemical quantity known as the total pi - electron energy of conjugated hydro carbon molecules. In recent times analogous energies are being considered, based on Eigen values of a variety of other graph matrices. In 1978, I.Gutman [1] defined energy mathematically for all graphs. Energy of graphs has many mathematical properties which are being investigated. The ordinary energy of an undirected simple finite graph G is defined as the sum of the absolute values of the Eigen values of its associated matrix. i.e. if mu(1), mu(2), ..., mu(n) are the Eigen values of adjacency matrix A(G), then energy of graph is Sigma(G) = Sigma(n)(i=1) vertical bar mu(i)vertical bar Laura Buggy, Amalia Culiuc, Katelyn Mccall and Duyguyen [9] introduced the more general M-energy or Mean Energy of G is then defined as E-M (G) = Sigma(n)(i=1)vertical bar mu(i) - (mu) over bar vertical bar, where (mu) over bar vertical bar is the average of mu(1), mu(2), ..., mu(n). A subset M subset of V (G), in a graph G (V, E), is called a monopoly set of G if every vertex v is an element of (V - M) has at least d(v)/2 neighbors in M. The minimum cardinality of a monopoly set among all monopoly sets in G is called the monopoly size of G, denoted by mo(G) Ahmed Mohammed Naji and N.D.Soner [7] introduced minimum monopoly energy E-MM [G] of a graph G. In this paper we are introducing the minimum mean monopoly energy, denoted by E-MM(M) (G), of a graph G and computed minimum monopoly energies of some standard graphs. Upper and lower bounds for E-MM(M) (G)are also established.Publisher's Versio
Photon transport in thin disordered slabs
We examine using Monte Carlo simulations, photon transport in optically 'thin' slabs whose thickness L is only a few times the transport mean free path l∗, with particles of different scattering anisotropies. The confined geometry causes an auto-selection of only photons with looping paths to remain within the slab. The results of the Monte Carlo simulations are borne out by our analytical treatment that incorporates directional persistence by the use of the Ornstein-Uhlenbeck process, which interpolates between the short time ballistic and long time diffusive regimes
Evaluation of bupirimate against rose powdery mildew
Bupirimate 25% Emulsifiable concentrate (EC) was evaluated for efficacy on Sphaerotheca pannosa, the causal agent of rose powdery mildew in vivo. In this experiment Bupirimate 25% EC 6 ml/L and 4 ml/L effectively reduced the powdery mildew infection over rest of the treatments and improved the flower yield. Moreover, application of Bupirimate 25% EC at the doses of 2, 4 and 6 ml/L and even at higher dose 8 ml/L did not show any phyto-toxic symptoms on rose plant. Thus, Bupirimate 25% EC may be considered as compared to other fungicides
Ionospheric response to the 2009 sudden stratospheric warming over the equatorial, low, and middle latitudes in the South American sector
The present study investigates the ionospheric total electron content (TEC) and F-layer response in the Southern Hemisphere equatorial, low, and middle latitudes due to major sudden stratospheric warming (SSW) event, which took place during January-February 2009 in the Northern Hemisphere. In this study, using 17 ground-based dual frequency GPS stations and two ionosonde stations spanning latitudes from 2.8°N to 53.8°S, longitudes from 36.7°W to 67.8°W over the South American sector, it is observed that the ionosphere was significantly disturbed by the SSW event from the equator to the midlatitudes. During day of year 26 and 27 at 14:00 UT, the TEC was two times larger than that observed during average quiet days. The vertical TEC at all 17 GPS and two ionosonde stations shows significant deviations lasting for several days after the SSW temperature peak. Using one GPS station located at Rio Grande (53.8°S, 67.8°W, midlatitude South America sector), it is reported for the first time that the midlatitude in the Southern Hemisphere was disturbed by the SSW event in the Northern Hemisphere.Fil: Fagundes, P. R.. Universidade do Vale do Paraíba; BrasilFil: Goncharenko, L. P.. Massachusetts Institute of Technology; Estados UnidosFil: De Abreu, A. J.. Universidade do Vale do Paraíba; BrasilFil: Venkatesh, K.. Universidade do Vale do Paraíba; BrasilFil: Pezzopane, M.. Istituto Nazionale Di Geofisica E Vulcanologia; ItaliaFil: De Jesus, R.. Universidade do Vale do Paraíba; BrasilFil: Gende, Mauricio Alfredo. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Coster, A. J.. Massachusetts Institute of Technology; Estados UnidosFil: Pillat, V. G.. Universidade do Vale do Paraíba; Brasi
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